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DIGITAL INTERFACES
Kepco's Single Address, Multiple
Instrument System for the Digital
Control of Kepco Power Supplies
Modern desk-top computers typically
Model TMA 4882-27 1U rack housing support RS 232 and can drive IEEE 488.2
with the help of a plug-in card. Many Kepco
TMA 4882-27 power supplies directly communicate with
these two digital buses. Their limitations,
Kepco's TMA are power supply controllers to program, control and however, in terms of the number of
monitor the output of up to 27 Kepco power modules in the MAT, MST instruments supported and the distance that
and BOP-TMA series at distances up to 1000 feet (300meters). can be covered, have led Kepco to adopt a
The Kepco TMA 4882-27 controller receives commands and transmits data serial bus scheme to distribute signals to
to a host computer over the bi-directional digital control bus IEEE 488.2 or multiple power supplies.
over a serial communications link using RS 232. Kepco model TMA 4882-27
Kepco's single address, multiple instrument
supports both CIIL (Control Intermediate Interface Language) and SCPI,
the Standard Commands for Programmable Instruments. serial bus is based on the IEEE 1118 protocol.
By choosing a 375KHz data rate and limiting
The controller continuously monitors the status of each power module for it to 27 talk-listen power supplies, we are
the correctness of the programmed voltage or current, overvoltage, overcur- able to provide communications to our
rent, crowbar, overtemperature, power loss, output enable, polarity reversal power supplies over a 300m (1000') path.
status and other fault conditions. Any changes from normal set conditions
The operation of this serial link is entirely
will generate error flags reported over the communications bus.
transparent to users. The communication
For catastrophic failures, a separate 2-wire discrete fault line output flag from PC to the IEEE 488.2 bus to Kepco's
(status monitor indicator) is activated for fast direct communication with serial bus to power supply and back is exactly
the host computer. Also, 2 pairs of isolated and non-isolated input lines as if the PC were talking to the power supply
are provided for fast remote emergency shut-down. on the IEEE 488.2 bus alone. The difference is
that there can be 27 power supplies spread over
300m of a daisy chained two-wire serial bus.
Kepco offers various hardware options to
facilitate communications between desk-top
computers and their common instrumentation
buses and Kepco's power supplies. The
TMA 4882-27 links either the GPIB or RS
232 to the single address multiple-instrument
bus that drives MST, MAT and BOP power
supplies. MST 488-27 accepts GPIB and RS
232 to drive the plug-in MST power modules.
The various BIT cards that plug into
Model TMA PC-27 plugs into a PC Kepco's low-voltage 100-400W BOP allow
these bipolar power supplies to interface with
TMA PC-27 the buses. A VXI interface is also offered.
Use a PC to directly control Kepco's M-series (MAT and MST) and
BOP-TMA power supplies.
PC-27 is a software emulator of Kepco's model TMA 4882-27. Where
TMA 4882-27 converts an IEEE 488.2 bus into the Kepco serial bus to
talk with a Kepco M-Series or BOP-TMA power supply, the model
TMA PC-27 communicates directly from your PC to the serial bus and
then to the M-series and BOP-TMA power supplies. TMA PC-27
comprises a board that will fit into your PC or compatible computer.
With the provided software, it allows your computer to emulate the
whole TMA function. The PC will communicate directly with up to 27
M-series and BOP-TMA power supplies providing all control and
communication functions without requiring an IEEE 488.2 (GPIB) card. AN ISO 9001 COMPANY
CompuMess 131-38 Sanford Avenue · Flushing, NY 11352 USA · Tel: (718)·461-7000 · Unterschleissheim
KEPCO, INC. · Elektronik GmbH · Lise-Meitner-Str.1 85716 Fax: (718) 767-1102
Email: hq@kepcopower.com · www.kepcopower.com/diginterface.htm
Tel 089-321501-0 · Fax 089-321501-11 · www.compumess.de · www.netzteile.de 59
TMA VXI-27
TMA VXI-27 supports the VXI bus by providing an interface path to
the Kepco M-series power supplies: MAT and MST. VXI, the VME bus
eXtension for Instrumentation is a recent standard for test and
measurement instruments that seeks to reduce the size of these
instruments, promote standardization, and allow instruments to share
resources such as cooling, chassis and power supply.
Kepco's power supplies are not the sources used to power up the
instruments-on-a-card that comprise a VXI card cage. Rather, they are
generators that work with the other instruments to stimulate the device
under test so that measurements can be made of its performance. As
generators, Kepco's programmable power supplies need to communicate
with the other instruments to receive instructions on where to set the
voltage (for example) and report back how much current is being drawn.
The Kepco TMA VXI-27 fills a single width slot in a VXI type "C"
enclosure and provides a serial output in the IEEE 1118 format.
For catastrophic failures, a separate 2-wire discrete fault line output flag
(status monitor indicator) is activated for fast direct communication with
Model TMA VXI-27 plugs into a VXI type C enclosure the host computer. Also, 2 pairs of isolated and non-
isolated input lines are provided for fast remote
emergency shut-down.
TMA VXI-27 SPECIFICATIONS
SPECIFICATION TYPE RATING/DESCRIPTION
Function To interconnect up to 27 power supplies with Kepco's
single address, multiple instrument, serial bus capability to the VXI bus.
Purpose To permit control of external power supplies via VXI
using either SCPI or CIIL programming languages
VXI Bus Capability Device (instrument) type VXI message-based servant interface with programmable interrupter capability
Command set Implements the command set of an I 4 instrument
Addressing Static configured address, switch selectable 1-254
Address space A16, sixteen address lines with normal handshake only
Interrupter Programmable interrupter software assigns interrupt levels between
Level (1) highest & Level (7) lowest priority
Data bus width D16, sixteen data lines for commands, status and data transfer
Module Specific Byte request; Byte available Data transfer using Word Serial Protocol
Commands Clear
Begin Normal Operation
End Normal Operation
Required for message-based instruments
Abort Normal Operation
Read Protocol
Read Protocol Error
Read interrupts:
Assign interrupter line Required for programmable interrupter instruments
Read interrupter line
Events Supported Control event: Enable, disable, request true and request false events
Through Interrupts Asynchronous mode control
Power Requirement Normal operation +5V, 2A from VXI backplane
Card Size VXI "C" size 9.19" x 13.39" (233.35 x 340mm)
VXI Mainframe Slots Card occupies one slot
Front Panel Connectors One 9-Pin "D"-type for serial bus; One 15-Pin "D"-type for aux. signals
On Line LED Green. Normally on. Indicates that
power is applied and the microsystem is on line.
Failed LED Red. Normally off. Indicates a failure condition.
"On" during power-on self test, goes off in less than 5 seconds.
Access LED Green. When on, it indicates that a VXI access cycle to the
module address has been executed.
CompuMess Elektronik GmbH ··Flushing, NY 11352 USA · Tel: (718) 461-7000 · Fax: (718) 767-1102
KEPCO, INC. · 131-38 Sanford Avenue Lise-Meitner-Str.1 · 85716 Unterschleissheim
60 Tel 089-321501-0 · hq@kepcopower.com · www.kepcopower.com/diginterface.htm
Email: Fax 089-321501-11 · www.compumess.de · www.netzteile.de